1. Field of the Invention
The present invention relates to a medical device for safe and convenient handling of used needle cannulas. More particularly, the present invention relates to a medical needle device that is adapted to automatically shield a needle cannula during normal use in a medical procedure.
2. Description of Related Art
Blood collection sets or intravenous (IV) infusion sets typically include a needle cannula having a proximal end, a distal end with a puncture tip, and a lumen extending therebetween. The proximal end of the needle cannula is mounted to a plastic hub having a central passage that communicates with the lumen in the needle cannula. A thin flexible thermoplastic tube is connected to the hub and communicates with the lumen in the needle cannula. The end of the plastic tube remote from the needle cannula may include a fixture for connecting the needle cannula to a separate medical device, such as a holder, a blood collection tube, and the like.
In order to reduce the risk of incurring an accidental needle-stick wound, protection of used needle cannulas becomes important. With concern about infection and transmission of diseases, methods and devices to cover used needle cannulas have become important and in great demand. Some needle assemblies commonly employ a safety shield that may be moved into shielding engagement with a used needle cannula without risking an accidental needle stick.
For example, a number of devices incorporate a pivoting shield assembly in which the shield can be pivoted away from the needle during use and pivoted about the needle after use, for protection from the used needle. Such pivotable shielding devices are well known for use in syringe devices, such as those disclosed in U.S. Pat. Nos. 5,599,318; 5,662,617; 5,669,889; 5,681,295; 5,733,265; 5,868,716; and 5,913,846, for example.
U.S. Pat. No. 6,309,376 discloses a winged intravenous infusion assembly which has a needle extending from a base member, with a pivotable housing attached to the base member for enveloping the needle after use. Pivoting of the pivotable housing to envelop and safely shield the used needle cannula, however, requires a two-handed operation by the user, and cannot be effectively accomplished until the device is completely removed from the patient due to the orientation of the pivotable housing with respect to the wings.
U.S. Pat. No. 6,254,577 discloses a hypodermic needle protector which is useful, for example, as an epicardial needle, and which constitutes a single piece of molded synthetic resin including a distal portion which forms a cap in which the distal end of the needle can be housed, and a proximal portion forming a base. The two portions are hinged together through a fold line, and the cap can be manually tilted by movement of the base to tilt or pivot the cap to a position protectively shielding the needle. Since pivoting of the cap portion is based on a fold and is achieved through corresponding manual movement of the base with respect to the fold, the structure is prone to wear due to wearing of the fold.
In view of the foregoing, there is a continuing need for a shielding medical needle device adapted to shield a used needle cannula once a medical procedure is completed.